Photovoltaic energy is becoming very significant source of electrical power. This is due to the fact that problems of scarcity and safety have limited the use of fossil and nuclear fuels and to recent advances in photovoltaic technology which have made possible the large scale manufacture of low cost, lightweight, thin film photovoltaic devices. It is now possible to manufacture large-scale, thin film silicon and/or germanium alloy materials which manifest electrical and optical properties equivalent, and in many instances superior, to their single crystal counterparts. These alloys can be economically deposited at high speed over relatively large areas and in a variety of device configurations and they readily lend themselves to the manufacture of low cost, large area photovoltaic devices. U.S. Pat. Nos. 4,226,898 and 4,217,364 both disclose particular thin film alloys having utility in the manufacture of photovoltaic devices which may be employed in the present invention. However, it is to be understood that the present invention is not limited to any particular class of alloys and may be practiced with a variety of semiconductor materials, including crystalline, polycrystalline, microcrystalline; and non-crystalline materials.
The power generated by a photovoltaic device is proportional to the illumination incident thereupon and if relatively large amounts of power are to be generated, fairly large collection areas are required. The roof and upper story areas of building structures are well illuminated and are generally not productively used. For some time now it has been known to place photovoltaic collectors on the top portions of buildings since the photovoltaic devices are advantageously positioned for illumination; and furthermore, they can function as a roofing structure. Roof mounted photovoltaic panels are shown, for example, in U.S. Pat. No. 4,336,413. U.S. Pat. No. 4,860,509 discloses a roofing material comprised of photovoltaic generating panels disposed in a pliant, waterproof roofing material.
Batten and seam construction is widely used in the building of roofs and the fabrication of wall panels. In this type of construction, a series of panels typically fabricated of metal or the like and having upturned edges, are fastened to a building in a side-by-side relationship so that edges of corresponding panels are disposed in a spaced-apart, parallel relationship. A cap-like batten member is affixed so as to cover adjoining edges and provide a water tight seal. It has been found that batten and seam panels are ideally suited for supporting photovoltaic devices. U.S. Pat. No. 4,189,881 and U.S. patent application 620,047(now U.S. Pat. No. 5,092,939) disclose batten and seam type constructions having photovoltaic devices supported thereupon. As disclosed in the foregoing patents, the panels are placed upon a roof, electrically interconnected and wired into the power system of the building.
It has been found that complications can arise as a result of the interconnections of photovoltaic structures of this type. As shown in the '881 patent, the photovoltaic devices are interconnected by wires running through conduits placed beneath the battens. As disclosed in the patent application 620,047, interconnection between panels is accomplished therebeneath. Both of these arrangements make it difficult to remove panels for replacement or for repair of the underlying roof structure. It is desired that there be provided a batten and seam type of photovoltaic roof construction which is modular in the sense that it allows for ready removal and replacement of individual panels without disturbance to remaining roof structure.
The present invention, as will be more fully disclosed hereinbelow, provides a system of batten and seam type photovoltaic roofs which allows for quick connection and disconnection of roofing panels in various electrically interconnected configurations. The present invention simplifies the installation, use, and service of photovoltaic roofing panels. These and other advantages of the present invention will be readily apparent from the drawings, discussion and description that follow.